In the past, all portable welding trucks carry at lease one oxygen and one fuel gas cylinder to be used in the trade of welding and cutting. Attached to the oxygen cylinder is an oxygen regulator. Attached to the fuel gas cylinder, which is an acetylene or propane tank, is a fuel gas regulator. The purpose of the regulator is to reduce the cylinder pressure to a working pressure usable for applicable processes--oxygen 2700 PSI reduced to 50-70 PSI, fuel gas 300 PSI reduced to 5-10 PSI. The fuel gas, either acetylene or propane (flammable or explosive), creates a flame from a spark or a flame and causes a burn. The oxygen, on the other hand, is noncombustible but supports or enhances a flame or spark.
Both oxygen and fuel gas regulators need to be protected at all times. When attached to the cylinders, they are subject to falls and collision damages. It is common for the inlet fitting of the regulator (1/4" threaded brass) to be broken off the regulator. If this happens, full cylinder pressure exhausts from the valve of the cylinder which, when full, is 2250 PSI at 70.degree. on the oxygen side and as much as 300 PSI on the fuel gas side. If there is a spark or flame, such as in a collision, oxygen supports this cause of action and accelerates this situation to intolerable circumstances, and the best of fire departments cannot deal with it.
Some states have adopted a policy already that the regulators cannot be attached to the cylinders in transit. They must be removed. In any case, there is nowhere for the cylinder regulators to go, except on the floor of the truck, where they are subject to dirt, grease guns and old oil cans. You should never allow oxygen components to come in contact with grease or oil, as these products contain carbon and become very unstable after they are compressed more than 18 PSI.
Walker No. 4,625,949 discloses a cabinet assembly having mounts for rigidly supporting regulators within the cabinet with passageways permitting hoses from the cylinders to extend into and be connected to the input line of the regulators.
Salvucci, Ser. No. 5,071,148 discloses a cart having a guard structure which protects the valve and gauge assembly from damage when separated from the cylinder.